A 51-year-old lesbian has given birth to her brother's baby after IVF treatment in America.

The revelation has provoked new fears that artificial insemination techniques are being misused.

It comes just weeks after a 62-year-old woman became France's oldest mother by using her brother's sperm to father a child.

The American woman, who is in a long term lesbian relationship had "long desired to be pregnant", according to doctors.

But she did not want to have a heterosexual relationship.

This kind of manufacturing of human life is completely unacceptable

Jack Scarisbrick,LIFE

Doctors at Columbia University carried out the IVF treatment, so she could "bear a child of common ancestry to herself", it was reported in the Internet medical journal Reproductive Biomedicine Online.

The menopausal woman was successfully implanted with a donor egg conceived by her brother's sperm after a previous attempt failed, and gave birth to a healthy baby.

The brother, who already has two children, has signed up to a legal agreement which states he will look after the child if his sister dies or becomes seriously disabled.

'Unusual' request

Dr Mark Sauer, of Columbia University, said that the request from the woman and her brother had been "unusual" and required the involvement of a large team of doctors.

"The desire to reproduce is perhaps one of the greatest desires known to man.

"The inability to conceive naturally, or with assisted reproduction, leaves many women feeling unfulfilled and
depressed."

He added: "Her partner was of similar age and also wished to assist in raising a
child."

Before the clinic agreed to the procedure, the woman and the brother had to undergo psychiatric tests and the
case was debated by the clinic's ethics committee.

Campaigners in the UK have reacted with anger at the procedure, with a pro-life charity calling it "deplorable".

Jack Scarisbrick. national chairman of LIFE, said: "This kind of manufacturing of human life is completely unacceptable.

"Children are not commodities to be created in this way."

Regulation problems

A spokeswoman for the Human Fertility and Embryology Authority told BBC News Online that the authority would not set an upper age limit for fertility treatment.

She added if a case such as this came to a UK clinic, the centre would have to carry out a "welfare of the child" assessment before it decided whether to press ahead with treatment.

But she said comprehensive rules would be extremely difficult to draw up.

"You can never regulate for all the things that people dream up."

But Professor Robert Edwards, who edits the online journal, said he thought the procedure was probably unique, and would be unlikely to happen again.

Professor Edwards, who worked with Patrick Steptoe on the first British test tube baby nearly 24 years ago, praised
the doctors, said: "But this was a very moving case which will bring great happiness to the mother, brother and the child itself."